uimaj-2.3.0-incubating/uimaj-core/src/main/java/org/apache/uima/util/XMLSerializer.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * 
 *   http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.uima.util;

import java.io.OutputStream;
import java.io.Writer;

import javax.xml.transform.OutputKeys;
import javax.xml.transform.Result;
import javax.xml.transform.Transformer;
import javax.xml.transform.TransformerConfigurationException;
import javax.xml.transform.TransformerException;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXResult;
import javax.xml.transform.sax.SAXTransformerFactory;
import javax.xml.transform.sax.TransformerHandler;
import javax.xml.transform.stream.StreamResult;

import org.apache.uima.UIMARuntimeException;
import org.apache.uima.internal.util.XMLUtils;
import org.w3c.dom.Node;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.SAXParseException;

/**
 * Utility class that generates XML output from SAX events or DOM nodes.
 */
public class XMLSerializer {
  private static final SAXTransformerFactory transformerFactory = (SAXTransformerFactory) SAXTransformerFactory
          .newInstance();

  private TransformerHandler mHandler;

  private Transformer mTransformer;

  private Result mResult;

  public XMLSerializer() {
    this(true);
  }

  public XMLSerializer(boolean isFormattedOutput) {
    try {
      mHandler = transformerFactory.newTransformerHandler();
      mTransformer = mHandler.getTransformer();

      if (isFormattedOutput) {
        // set default output format
        mTransformer.setOutputProperty(OutputKeys.INDENT, "yes");
        mTransformer.setOutputProperty(OutputKeys.ENCODING, "UTF-8");
        mTransformer.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "4");
        mTransformer.setOutputProperty(OutputKeys.METHOD, "xml");
      }

    } catch (TransformerConfigurationException e) {
      throw new UIMARuntimeException(e);
    }
  }

  public XMLSerializer(OutputStream aOutputStream) {
    this();
    setOutputStream(aOutputStream);
  }

  public XMLSerializer(OutputStream aOutputStream, boolean isFormattedOutput) {
    this(isFormattedOutput);
    setOutputStream(aOutputStream);
  }

  public XMLSerializer(Writer aWriter) {
    this();
    setWriter(aWriter);
  }

  public XMLSerializer(Writer aWriter, boolean isFormattedOutput) {
    this(isFormattedOutput);
    setWriter(aWriter);
  }

  public void setOutputStream(OutputStream aOutputStream) {
    mResult = new StreamResult(aOutputStream);
    mHandler.setResult(mResult);
  }

  public void setWriter(Writer aWriter) {
    mResult = new StreamResult(aWriter);
    mHandler.setResult(mResult);
  }

  public ContentHandler getContentHandler() {
    String xmlVer = mTransformer.getOutputProperty(OutputKeys.VERSION);
    boolean xml10 = xmlVer == null || "1.0".equals(xmlVer);
    return new CharacterValidatingContentHandler(!xml10, mHandler);
  }

  public void serialize(Node node) {
    try {
      mTransformer.transform(new DOMSource(node), mResult);
    } catch (TransformerException e) {
      throw new UIMARuntimeException(e);
    }
  }

  public void dom2sax(Node node, ContentHandler handler) {
    try {
      mTransformer.transform(new DOMSource(node), new SAXResult(handler));
    } catch (TransformerException e) {
      throw new UIMARuntimeException(e);
    }
  }

  public void setOutputProperty(String name, String value) {
    try {
      mTransformer.setOutputProperty(name, value);
    } catch (IllegalArgumentException e) {
      throw new UIMARuntimeException(e);
    }
  }  
  
  static class CharacterValidatingContentHandler implements ContentHandler {
    ContentHandler mHandler;
    boolean mXml11;
    
    CharacterValidatingContentHandler(boolean xml11, ContentHandler serializerHandler) {
      mHandler = serializerHandler;  
      mXml11 = xml11;
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#startElement(java.lang.String, java.lang.String, java.lang.String, org.xml.sax.Attributes)
     */
    public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException {
      for (int i = 0; i < atts.getLength(); i++) {
        String val = atts.getValue(i);
        checkForInvalidXmlChars(val, mXml11);
      }
      mHandler.startElement(uri, localName, qName, atts);
      
    }
    
    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#characters(char[], int, int)
     */
    public void characters(char[] ch, int start, int length) throws SAXException {
      checkForInvalidXmlChars(ch, start, length, mXml11);
      mHandler.characters(ch, start, length);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#endDocument()
     */
    public void endDocument() throws SAXException {
      mHandler.endDocument();
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#endElement(java.lang.String, java.lang.String, java.lang.String)
     */
    public void endElement(String uri, String localName, String qName) throws SAXException {
      mHandler.endElement(uri, localName, qName);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#endPrefixMapping(java.lang.String)
     */
    public void endPrefixMapping(String prefix) throws SAXException {
      mHandler.endPrefixMapping(prefix);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#ignorableWhitespace(char[], int, int)
     */
    public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException {
      mHandler.ignorableWhitespace(ch, start, length);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#processingInstruction(java.lang.String, java.lang.String)
     */
    public void processingInstruction(String target, String data) throws SAXException {
      mHandler.processingInstruction(target, data);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#setDocumentLocator(org.xml.sax.Locator)
     */
    public void setDocumentLocator(Locator locator) {
      mHandler.setDocumentLocator(locator);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#skippedEntity(java.lang.String)
     */
    public void skippedEntity(String name) throws SAXException {
      mHandler.skippedEntity(name);
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#startDocument()
     */
    public void startDocument() throws SAXException {
      mHandler.startDocument();
    }

    /* (non-Javadoc)
     * @see org.xml.sax.ContentHandler#startPrefixMapping(java.lang.String, java.lang.String)
     */
    public void startPrefixMapping(String prefix, String uri) throws SAXException {
      mHandler.startPrefixMapping(prefix, uri);
    }
    
    private final void checkForInvalidXmlChars(String s, boolean xml11) throws SAXParseException {
      final int index = XMLUtils.checkForNonXmlCharacters(s, xml11);
      if (index >= 0) {
        throw new SAXParseException("Trying to serialize non-XML " + (xml11 ? "1.1" : "1.0") + 
                " character: " + s.charAt(index)
            + ", 0x" + Integer.toHexString(s.charAt(index)), null);
      }
    }
    
    private final void checkForInvalidXmlChars(char[] ch, int start, int length, boolean xml11) throws SAXParseException {
      final int index = XMLUtils.checkForNonXmlCharacters(ch, start, length, xml11);
      if (index >= 0) {
        throw new SAXParseException("Trying to serialize non-XML " + (xml11 ? "1.1" : "1.0") + 
                " character: " + ch[index]
            + ", 0x" + Integer.toHexString(ch[index]), null);
      }
    }    
  }
}